When exposing for a scene, a light meter of a camera may select an aperture and shutter speed combination for the picture. Exposure bracketing involves taking additional pictures at slight under-exposure and slight over-exposure. The camera might have been misled by the light available and the main subject may be over- or under-exposed in a particular image. Taking more shots allows compensation for the variation in lighting. In challenging scenes, however, exposure bracketing might not be sufficient to guarantee taking a picture that meets the customer's expectations.
Examples of scenes that are challenging for capturing good pictures include fast action, low light, night, indoor, backlit, and close-up. For example, a scene may be taken where there is an abundance of light around a target subject and a lesser amount of light illuminating the background. If the camera closes down the aperture using a faster shutter speed, the target subject might be under-exposed. An extra shot taken at slight over-exposure may properly expose the target subject but over-expose the surroundings. In another example, a scene may be taken where the background might be too dark. Where a camera exposes for the lack of light by opening up the aperture and/or using a slower shutter speed, the target subject might be over-exposed. An extra shot taken at slight under-exposure may properly expose the target subject but under-expose the surroundings. In both of these examples, better results might be obtained by changing other settings besides exposure.